ML20052B300

LER 82-025/03L-0:on 820326,min Average Ice Weight of Sample Baskets from Radial Rows 8 & 9 Group 2 Found to Be Less than 1,220 Lb/Basket at 95% Level of Confidence.Caused by Migration of Ice Mass Away from Crane Wall.Ice Mass Added

ML20052B300
Person / Time
Site:	Cook
Issue date:	04/23/1982
From:	Palmer R INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20052B289	List: ML20052B288 ML20052B292 ML20052B300
References
LER-82-025-03L, LER-82-25-3L, NUDOCS 8204300268
Download: ML20052B300 (2)

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LICENSEE EVENT REPORT

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60 61 DOCKET NUMBER 68 69 EVENT DATE 14 75 REPORT D ATE 80 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES Oto iO i2l l DURING A SCHEDULED SURVEILLANCE TEST OF THE ICE CONDENSER BASKETS, THE MINIMUM l i o i 3, i AVERAGE ICE WEIGHT OF SAMPLE BASKETS FROM RADIAL R0WS 8 AND 9 GROUP 2 WAS FOUND TO l io i ,i BE LESS THAN 1220 POUNDS / BASKET AT A 95% LEVEL OF CONFIDENCE. THIS CONDITION WAS l

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44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS l iia l l ICE LOSS WAS CAUSED BY THE MIGRATION OF ICE MASS AWAY FROM THE CRANE WALL, WHICH l li ii i j OCCURRED DUE TO TEMPERATURE GRADIENT INDUCED AIR CURRENTS. ICE MASS WAS ADDED TO THEI

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ATTACHMENT TO LER#82-025/03L-0 SUPPLEMENT TO CAUSE DESCRIPTION THE MIGRATION OF ICE MASS AWAY FROM THE CRANE WALL OCCURRED DUE TO TEMP-ERATURE GRADIENT INDUCED AIR CURRENTS. THESE TEMPERATURE GRADIENTS ARE DUE TO THE PROXIMITY OF THE CRANE WALL TO THE STEAM GENERATORS. AS THIS MECHANISM WAS APPARENT FROM PREVIOUS DATA, SOME MIGRATION OF ICE MASS WAS EXPECTED. HOWEVER, THE MAGNITUDE WAS HIGHER THEN PREDICTED.

PRIOR TO ICE BASKET WEIGHING, A TOTAL OF 17 AIR HANDLER UNITS WERE INOPERABLE.

9 0F THE INOPERABLE AIR HANDLERS WERE IN GROUP 2, WITH 5 ALONG THE GROUP 2 CRANE WALL AND 4 ALONG THE GROUP 2 CONTAINMENT WALL. AS A RESULT OF THE LARGE NUMBER OF IN0PERABLE AIR HANDLERS, PARTICULARLY IN THE GROUP 2 CRANE WALL AREA, THE MIGRATION LOSS WAS LARGER THEN EXPECTED IN THIS REGION. THE REASON FOR THE LARGE NUMBE0 0F INOPERABLE AIR HANDLERS WAS DUE TO THE HIGH AIRBORNE RADI0 ACTIVITY CONCENTRATION IN CONTAINMENT WHICH, AS A RESULT OF ALARA PRACTICES, PREVENTED MAINTENANCE DURING UNIT OPERATION. ALL AIR HANDLERS WERE REPAIRED AND RETURNED TO SERVICE PRIOR TO THE UNIT STARTUP.

ICE MASS WAS ADDED TO THOSE BASKETS NOT MEETING TECHNICAL SPECIFICATION MINIMUM LIMITS. ICE WAS ADDED TO BOTH THE TOP AND BOTTOM OF THE BASKETS, REQUIRING SIGNIFICANT EFFORT IN DEVELOPING THE ICE ADDITION METHOD.

l TO PREVENT RECURRENCE A PROGRAM HAS BEEN INSTITUTED TO MONITOR AIR HANDLER AND GLYCOL CHILLER PERFORMANCE DAILY. ANY DEGRADATION IN REFRIGERATION CAPACITY WILL BE IDENTIFIED AND CORRECTIVE ACTION TAKEN AS PERMITTED BY ALARA PRACTICES. FURTHERM0RE, A TASK FORCE WILL BE FORMED TO REVIEW METHODS FOR FURTHER REDUCTION OF SUBLIMATION RATES IN ALL R0WS AND SPECIFICALLY THOSE NEAREST THE CRANE WALL. THIS TASK FORCE WILL ALSO Ei!ALUATE REQUIRED ICE BASKET MINIMUM WEIGHT REQUIREMENTS AND REFINEMENT OF ICE MASS ADDITION TECHNIQUES.

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